1. Field of the Invention
The present invention generally relates to networking and, more particularly, to a certificate based Authentication Authorization and Accounting (AAA) scheme for loose coupling interworking between two different access networks.
2. Related Art
Typically, Authentication, Authorization and Accounting (AAA) are required to access and utilize networks such as cellular networks and Wireless Local Area Networks (WLANs). However, the implementing of AAA can be difficult as well as requiring additional software and/or hardware in the case of interworking between two different radio access networks that do not belong to the same administrative domain and do not share the same AAA schemes.
There are two main types of interworking between cellular networks and WLANs: tight coupling and loose coupling. In a loose coupling scenario, the WLAN and the cellular network have independent data paths but the AAA for WLAN users relies on cellular network AAA functions. However, the cellular network AAA protocols (MAP/SS7) are incompatible with Internet Protocol (IP) based protocols used by WLAN users. Two approaches have been proposed. In the first approach, an AAA interface is provided in the cellular network Home Location Register (HLR). This requires either duplicating HLR data or providing a protocol converter between Radius/Diameter and MAP. In the second approach, if the Mobile Terminal (MT) uses a Subscriber Identity Module (SIM) card based authentication mechanism (e.g., NOKIA's wireless operator LAN), then the AAA will follow the cellular procedure. An AAA InterWorking Function (IWF) is necessary to interface with the HLR and an MT. Functionality wise, it is similar to a Serving GPRS (General Packet Radio Service) Support Node (SGSN) or Mobile Switching Center (MSC) from the AAA perspective except AAA traffic is carried through IP.
With both approaches, special interworking functions or gateways need to be deployed by the cellular operators. With the second approach, users are required to have a SIM card for WLAN access, but most WLAN users do not have SIM cards available on their laptops or Personal Digital Assistants (PDAs).
Accordingly, it would be desirable and highly advantageous to have an Authentication Authorization and Accounting (AAA) scheme for the case of interworking between two different networks that do not belong to the same administrative domain and do not share the same AAA schemes, where the AAA scheme does not require the deployment of a special interworking function to bridge between the two different types of networks.